Conversion of hydrocarbons



Patented Sept. 18, 1945 UNITED STATES PATENT OFFICE CONVERSION OF EYDROGARBONS Herman Pines and Vladimir N. Ipatiefl, Riverside, 111., assignors to Universal Oil Products Company, Chicago, 111., a corporation or Dela.-

ware

No Drawing. Application January 29, 1043,

- Serial No. 478,972

7 Claims. (01. 260-666) This invention relates to a process for eiiecting hydrocarbon conversions and more particularly to a process for converting alkyl cyclopentane hydrocarbons into alkyl cyclohexanes by reacting said alkyl cyclopentane hydrocarbons with paraiilnic hydrocarbons in the presence of a catalyst.

ess.

The present process is a contribution to the art One specific embodiment of the present invention comprises a process for reacting an alkyl cyclopentane hydrocarbon .with a paraflinic hydrocarbon in the presence of an alkylating cat alyst to form a substantial yield of alkylated and polyalkylated cyclohexane hydrocarbons.

The present process is particularly concerned with a simultaneous cleavage or breaking of a paramnic hydrocarbon and the alkylation of an alkyl cyclopentane with fragments resulting irom said cleavage or breaking of a paraflinic hydrocarbon. Furthermore, it appears that isomerization can accompany alkylation when an alkyl cyclopentane hydrocarbon is destructively aliwlated with a paramnic hydrocarbon. The following equahlon illustrates the destructive alkylation of methyl cyclopentane with iso-octane:

The above equation indicates that methyl cycyclopentane may be reacted with 2,2,4-trimethylpentane to form 1,2-dimethyl-4-ethylcyclohexare together with isobutane. Other branched chain paraflinic hydrocarbons and less-branched chain parafiinic hydrocarbons can also undergo a similar reaction under suitable conditions of carbons and parafllnic hydrocarbons of lower molecular weight than those charged to the proc- The ease with which. the above reaction occurs is probably due to' the presence of a tertiary carbon atom in the alkyl cyclopentane molecule.

Because of the difliculty in following the character 01 such reactions and the possible formation of certain proportions of intermediate addition compounds with the catalyst in reactions of the present type. the above explanation is not ofiered as being entirely adequate. mention of the formation of small amounts oi .gaseous hydrocarbons of low molecular weight such asmethane and ethane which sometimes occurs to a minor extent. However, under properly controlled "conditions, decomposition reactions to undesired gaseous hydrocarbons may be kept low and the alkylation may be regulated by controlling the temperature, the nature and amount or the catalyst. the proportion of parafilnic hydrocarbons to alkyl cyclo'pentane hydrocarbons, etc., so that'high yields of the desired compounds will be produced.

We have discovered that isomerization and alkylation of alkyl cyclopentane hydrocarbons can be accomplished simultaneously and more advantageously by the process of the present invention thanby isomerization alone. In this process, the alkyl cyclopentanes are reacted with straight and/or branched chain parafiins in the presence or an alkylating catalyst including suli'uric acid, hydrogen fluoride, mixtures of hydrogen fluoride and boron fluoride, and Friedel- Crafts type metal halides together with a hydrogen. halide. Under the preferred conditions of operation, which are discussed hereinafter in relation to the difierent aikylating catalysts, an almlation productis formed consisting not of more highly alkylated cyclopentane hydrocarbons but of alkylated cyclohexane hydrocarbons. In other words, isomerization occurred either before, after, or during the alkylation reaction. By this process, the alkylation of alkyl cyclopentane hydrocarbons with parafiinic hydrocarbons, includin isoparafflns and normal paraflins, to form alkyl cyclohexane hydrocarbons is accomplished rapidly under operating conditions which are relatively easy to control.

Another advantage of the process is the fact that nearly complete conversion of the alkyl cyclopentane hydrocarbons into alkyl cyclohexanes can be obtained. Furthermore, the cyclohexane hydrocarbons formed by this process may be operation to form alkylated cyclohexane hydro- 5s separated from unconverted cyclopentane by- It also omits drocarbons and dehydrogeuated catalytically or thermally into alkyl benzene hydrocarbons while the unconverted or incompletely converted alkyl cyclopentane hydrocarbons are returned to further treatment with paraflinic hydrocarbons in the presence of an alkylating catalyst as herein set forth.

The diflerent allwl cyclopentane hydrocarbons and paraiilnic hydrocarbons employed in the process need not be entirely pure as any hydrocarbon fraction or fractions containing alm cyclopentane hydrocarbons and paramnic hydrocarbons may be utilized in the process. Thus, a

7 hydrogen fluoride or mixtures of hydrogen fluoride and boron fluoride, a reactor temperature of from about -20 to about 200 C. is employed at a pressure of generally not more than about 35 atmospheres; while sulfuric acid is utilizable generalhr at a temperature of from about 5 to about 120 C. when employing catalysts containing an acid of phosphorus, such as solid phosphoric acid, the temperature utilized is from about 100 to about 450 C. and the pressure is generally between about 1 and 70 atmospheres. Catalysts of the Friedel-Crafts type are utilizable under diiferent conditions of operation depending upon the particular Frledel-Crafts type catalyst employed. 'I'hus, aluminum chloride may be utilized at a temperature of from about 'l0 to about 150 C. while ferric chloride requires a somewhat higher average temperature and zinc chloride is utilizable only at still higher temperatures and particularly at a temperature of from about 150 to about 450 C.

The details of operation of the present process are relatively simple since alkyl cyclopentane hydrocarbons are liquid under ordinary conditions of temperature and pressure. Accordingly, the process of the present invention is carried out by contacting an alkyl cyclopentane hydrocarbon with a parafilnic hydrocarbon generally containing 4 or more carbon atoms per molecule in the presence of an alkylating catalyst under the preferred operating conditions until alkylation has occurred and a substantial yield of an essentially saturated hydrocarbon product is formed containing a relativelyhigh proportion of alkyl cyclohexane hydrocarbons. The molar ratio of alkyl cyclopentane hydrocarbons to parafllnic hydrocarbons should be greater than 1 and preferably greater than 3, the exact ratio being somewhat dependent upon the particular alkyl cyclopentane and paraflinic hydrocarbons charged to the process. The ratio of alkyl cyclopentane hydrocarbon to parailinic hydrocarbons charged is subject to some variation and is affected considerably by the method of introducing the c hydrocarbon, the efliciency of mixlngve I It is advisable to carry out the process of the present invention at as low a temperature as assasoo the rate of undesirable reactions which frequently result in deposition and/or degradation 7 of the desired alkylation product.

possible and as is practical, since at higher temperatures there is generally a marked increase in While the process of the present invention may be eii'ected in either batch or continuous types of operation, it is usually carried out on a continuous basis by withdrawing from the reaction zone a complex mixture of excess unreacted alkyl cyclopentanes, desired alkylated cycloh'exanes, higher boiling hydrocarbons, and catalyst; said complex mixture being withdrawn at substantially the same rate as that at which the hydcarbons charged are supplied to the alkylation reactor. At least a portion or the recovered used catalyst and unreacted alkyl cyclopentanes may be recycled to further treatment with parafllnic hydrocarbons in the presence of some freshly added alkylating catalyst.

Batch type operation of the present process may be carried out by gradually introducing a paraflinic hydrocarbon fraction or a paraflin containing fraction to a reaction vessel containing a mixture of the alkyl cyclopentane hydrocarbon and the catalyst. The reaction vessel is preferably equipped with an eflicient mixing or stirring device so as to insure intimate contact of the reacting hydrocarbons and catalyst. Upon completion of the alkylation reaction, a hydrocarbon product is separated from the catalyst and said hydrocarbon product is further fractionally distilled to separate alkylated cyclohexane hydrocarbons from unconverted or incompletely converted paraiilnic and cycloparafllnic hydrocarbons which are returned to further treatment in the presence of an alkylating catalyst as hereinabove set forth.

The following example indicates results obtainable by the present process, although it is introduced with no intention of limiting the scope of the invention in exact correspondence thereto.

4 molecular proportions of methyl cyclopentane are reacted with 0.5 molecular proportions of 2,2,4-trimethyl pentane in the presence. of hydrogen fluoride at a temperature 010100 C. The resultant reaction mixture, after separation therefrom of unconverted methyl cylclopentane and 2,2,4-trimethyl pentane, contains substantial amounts of allgvlated cyclohexane hydrocarbons.

The character of the present invention and its novelty and utility in producing alkyl cyclohexane hydrocarbons can be seen from the preceding specification and example, although neither section is intended to limit unduly its generally broad scope.

We claim as our invention:

1. A process for producing substantial yields of alkyl cyciohexane hydrocarbons which comprises reacting an alkyl cyclopentane hydrocarbon and an isoparaflinic hydrocarbon in the presence of an alkylating catalyst while maintaining a molar excess of alkyl cyclopentane hydrocarbon to isoparaflinic hydrocarbon throughout the reaction.

2. A process for producing substantial yields of alkyl cyclohexane hydrocarbons which comprises reacting an alkyl cyclopentane hydrocarbon and an isoparaflinic hydrocarbon in the presence of an alkylating catalyst comprising sulfuric acid as its essential active ingredient.

3. A process for producing substantial yields of alkyl cyclohexane hydrocarbons which comprises reacting an alkyl cyclopentane hydrocara,sas,soo

' action.

6. A process for producing substantial yields of alkyl cyciohexane hydrocarbons which comprises reacting an alkyl cyclcpentane hydrocarbon and 7 an isoparaiiinic hydrocarbon in the presence of an alkylating catalyst while maintaining a molar ratio of alkyl cyclopentane hydrocarbon to isoparamnic hydrocarbon or more than three throughout the reaction.

7. A process for producing substantial yields oi alkyi cyclohexane hydrocarbons which comprises reacting an alkyl cyciopentane hydrocarbon and a. paramnic hydrocarbon in the presence of an alkylating catalyst while maintaining a molar ratio of alkyl cyclopentane hydrocarbon to paraiiinic hydrocarbon of more than three throughout the reaction.

HERMAN PINES. VLADIMIR N. IPA'IfIEI'I'. 

